Gluing Life Together. Computer Simulation in the Life Sciences: An Introduction

Over the course of the last three decades, computer simulations have become a major tool of doing science and engaging with the world, not least in an effort to predict and intervene in a future to come. Born in the context of the Second World War and the discipline of physics, simulations have long spread into most diverse fields of enquiry and technological application. This paper introduces a topical collection focussing on simulations in the life sciences. Echoing the current state of tinkering, fast developments, segmentation of knowledge and interdisciplinary collaboration, and in an effort to bridge the science-humanities divide, the contributors to this collection come from multiple disciplinary backgrounds, including information studies, cognitive sciences, philosophy and biology. The ambiguous character of simulations, their cutting across scientific disciplines, analysis and prediction, understanding and doing, gave rise to their success in contemporary life sciences and has been the object of much scientific debate. One of the main aims of this topical collection, by contrast, is to call into question the assumption of an obvious use and easy transfer of methods between fields of knowledge as diverse as, e.g. physics and biology. The collection presents historical case studies from various biological sub-fields. The articles study how simulations are used and the ways they contribute specifically to our understanding of life. Taking up Sergio Sismondo’s description of simulations as “compromises” and “glue”, they also critically engage with the question of what exactly the life sciences have been gluing together over the last two decades

Body Image [brochure and video]

Every person has a view of their body image. However, some people’s views of their body image are more skewed than others. College students are no exception to this, in fact, college students may be at a higher risk than any other group of people to have a skewed body image. The student project completed on the subject showed that as the definition of body image upholds everyone looks at their bodies differently. Having a skewed body image can lead to: working out in excess, never being relaxed about his/her body, putting him/herself down a lot, checking weight more than once per day, constantly looking in the mirror, and a change in eating patterns which could also lead to eating disorders. There is almost no way to escape a person wanting to change his/her body image. However, one must be realistic about their body and set realistic goals for what they want to change

On the sensitivity of HeI singlet lines to the FeIV model atom in O stars

Recent calculations and analyses of O star spectra have revealed discrepancies between theory and observations, and between different theoretical calculations, for the strength of optical HeI singlet transitions.We investigate the source of these discrepancies. Using a non-LTE radiative transfer code we have undertaken detailed test calculations for a range of O star properties. Our principal test model has parameters similar to those of the O9V star, 10 Lac. We show that the discrepancies arise from uncertainties in the radiation field in the HeI resonance transition near 584Angs. The radiation field at 584Angs. is influenced by model assumptions, such as the treatment of line-blanketing and the adopted turbulent velocity, and by the FeIV atomic data. It isshown that two FeIV transitions near 584Angs can have a substantial influence on the strength of the HeI singlet transitions. Because of the difficulty of modeling the HeI singlet lines, particularly in stars with solar metalicity, the HeI triplet lines should be preferred in spectral analyses. These lines are much less sensitive to model assumptions.Comment: 7 pages, 9 figures, accepted for publication in A&

Annealing-Induced Changes in the Nature of Point Defects in Sublimation-Grown Cubic Silicon Carbide

In recent years, cubic silicon carbide (3C-SiC) has gained increasing interest as semiconductor material for energy saving and optoelectronic applications, such as intermediate-band solar cells, photoelectrochemical water splitting, and quantum key distribution, just to name a few. All these applications critically depend on further understanding of defect behavior at the atomic level and the possibility to actively control distinct defects. In this work, dopants as well as intrinsic defects were introduced into the 3C-SiC material in situ during sublimation growth. A series of isochronal temperature treatments were performed in order to investigate the temperature-dependent annealing behavior of point defects. The material was analyzed by temperature-dependent photoluminescence (PL) measurements. In our study, we found a variation in the overall PL intensity which can be considered as an indication of annealing-induced changes in structure, composition or concentration of point defects. Moreover, a number of dopant-related as well as intrinsic defects were identified. Among these defects, there were strong indications for the presence of the negatively charged nitrogen vacancy complex (NC–VSi)−, which is considered a promising candidate for spin qubits

Different no more: Country spreads in advanced and emerging economies

Interest-rate spreads fluctuate widely across time and countries. We illustrate this on the basis of about 3,100 quarterly observations for 21 advanced and 17 emerging economies since the early 1990s. Prior to the financial crisis, spread fluctuations in advanced economies are an order of magnitude smaller than in emerging economies. After 2008 their behavior has largely converged along a number of dimensions. We also provide evidence on the transmission of spread shocks and find it similar across sample periods and country groups. The importance of spread shocks as a source of output fluctuations in advanced economies has increased after 2008

Advanced parametrical modelling of 24 GHz radar sensor IC packaging components

This paper deals with the development of an advanced parametrical modelling concept for packaging components of a 24 GHz radar sensor IC used in automotive driver assistance systems. For fast and efficient design of packages for system-in-package modules (SiP), a simplified model for the description of parasitic electromagnetic effects within the package is desirable, as 3-D field computation becomes inefficient due to the high density of conductive elements of the various signal paths in the package. By using lumped element models for the characterization of the conductive components, a fast indication of the design's signal-quality can be gained, but so far does not offer enough flexibility to cover the whole range of geometric arrangements of signal paths in a contemporary package. This work pursues to meet the challenge of developing a flexible and fast package modelling concept by defining <i>parametric</i> lumped-element models for all basic signal path components, e.g. bond wires, vias, strip lines, bumps and balls

Influence of Morphological Changes in a Source Material on the Growth Interface of 4H-SiC Single Crystals

In this study, the change of mass distribution in a source material is tracked using an in situ computer tomography (CT) setup during the bulk growth of 4H- silicon carbide (SiC) via physical vapor depostion (PVT). The changing properties of the source material due to recrystallization and densification are evaluated. Laser flash measurement showed that the thermal properties of different regions of the source material change significantly before and after the growth run. The Si-depleted area at the bottom of the crucible is thermally insulating, while the residual SiC source showed increased thermal conductivity compared to the initially charged powder. Ex situ CT measurements revealed a needle-like structure with elongated pores causing anisotropic behavior for the heat conductivity. Models to assess the thermal conductivity are applied in order to calculate the changes in the temperature field in the crucible and the changes in growth kinetics are discussed